>> > how about the 4 channel mic?
>> What about it? The discussion stopped when I asked what should be the
> name for the device. I asked whether "4channelinput" would be good, but
> got no answers. At PulseAudio side we figured that "hw" works well
> enough in practice
http://www.rrfx.net/2009/11/ps3-eye-4-channel-audio-tests-on-ubuntu.html
the geometry of the microphone array is an important factor for how to
perform downmixing to mono as there are delay between the four mics and the
channel map of mic array is different from the channel map of surround
speakers